Improved cut-off valve



UNITED STATES PATENT OEETCE.

ALEXANDER K. RDER, OF HYDEVILLE, VERMONT.

IMPROVED CUT-OFF VALVE.

Specification Forming part of Letters Patent No. 35,] 76, dated May` 6, 18672..

To all whom t may concern:

Be it known that I, ALEXANDER K. RIDER, of Hydeville, in the county of' Rutland and State of Vermont, have invented a new and useful Improvement in Variable CutfOtifs for Steam-Engines; and I do hereby declare that' the 'following is a full, clear, and exact delscription of the same, reference being had to the accompanying drawings, forming part of this specification, in whieh- Figure l is a side elevation of a horizontal steam-engine with my improvement, representing it with the bonnet: ot' the val\'f'e-ehest removed to expose the cut-oli' to view. Fig. 2 is a plan of the same, with the cylinder and lvalve-ehest in section. Fig. is a transverse vertical section through the cylinder, valveehest, main valve, and ent-ott'. Fig. 4: is a side view of the hand-gear for varying the point of stroke at which the steam is eut ofi?. Fig. 5 is a front:- view of the main valve, and Fig. (j is a back view of: the same.

Similar letters of reference indicate correspondin parts in the several figures.

This invention relates to that class of eutofs in which the eut-oli' valve is fitted to the back otf a main slide-valve,through which the induction and eduetion ot' steam to and from the cylinder ot' the engine is ettected. l

It consists in the construction of' the cutofl' valve with .its ends oblique to the direction of the movement of the main valve, and in so applyii'lg the said valve to the back ot' the main valve that it may work transversely thereto without interfering` with the longitudinal movement of the latter valve, which has the outer orifices oi' its steam-ports arranged obliqnely to correspond with the oblique ends ot the cut-ott' valve. This construction o'f' the valves, seat, and ports permits the point ot cutting of'f to be varied throughout the whole length ot' the stroke ot' the piston by the transverse movement off the cutoft' valve either by hand or by the `governor.

To enable others skilled in the art to make and applT my invention, I will proceed to describe it with reference to the drawings.

A is the cylinder, B the piston, "3 the piston-rod, B2 the coimeeting-rod, C the crank, and D the crank-shaft, all constructed and arranged in the usual manner.

E is the Valve-chest, and a a the valve-seat,

having the same system of ports, l), b', and e, eommiu'iieating with the cylinder and the exhaust-pipe, as is commonly provided when a single slide-valve is used to effect the induetion and eduetion of steam at both ends of the cylinder.

F is the slide-valve, having its faee construetetfl in the manner common to the threeport valve, as shown in Fig. 5, but having its back parallel lengthwise with its face, but hollowed out transversely, in the manner best shown in Fig. l, to torm a seat for the cnt-ofi valve G, which is representml of the form of a segment or sector ot a cylinder. The indnction-ports d d', provided in the said valve F, have their inner mouths or orifices-that is to sa v,those next its seat o u-at right angles to the direction of the movement oil the said valve, but their outer orifices-that is to sav,

those in the concave seat of the entoi valvearranged obliquelvv in opposite directions, as shown in Figs. i and t3. This valve F is operated by an eccentric, ll, on the crank-shaft in the usual manner.

The segment or sector-shaped cut-oli' valve G, whose tace constitutes a ].)ortion ot' the surt'aee of a c vlinder, is attached securelyY to a concentric stem, f, which is arranged parallel with the stem and face of the main valve, and which is tit-ted to work through shitting-boxes in the ends el' the valve-chest. The oblique ends s s of this valve (i are parallel with the edges of' the oblique orifices ot the ports tl d oi the main valve and meet in a point, and the length of' the said valve mayY be such that it will just cover the outer edges of both ports dd when its sides j, which are lntrallel withits Vaxis and its point lap eqnall v over the ends of the said ports, and its width may be about double that ofthe length of the ports (l d,meas ured across the back of the valve F. The stem is connected by a swivel, g, outside of the valve-chest, with the rod i', attached to an eccentric, l, ou the crank-slmft. This swivel allows the valve-stein f and valve (l to he turned about their axis, either by hand or b v agovernor connected with the stem, without interfering with the operation of the eccentrie I and during the longitudinal movement ot' the said valve produced by the said eccentric. The eccentric I may have the same throwv as that of H, which works the main valve, and when it has such throw and the length of the valve is as before described the said eccentric I should be set about one-eighth of a revolution in advance of II. The stem f is represented as having firmly secured to it an arm, Z, which serves as a handle by which to turn it and the valve G by hand to vary the point of cut off, and a dog, m, attached to the said lever, is made the means of connecting the governor-slide fn, the said dog engaging with a notched sector-plate, p, (see Figs. l, 2, and 4,) which is so fitted to the stem as to allow the latter to turn in it when necessary to alter the adjustment of the valve, and the said sector-plate having rigidly attached to it an arm, q, which is connected by a rod, o', with the governor-slide.

In order to enable the stem and valve to move longitudinally ind epen d ently of the handle Z and sector-plate p, the stem is fitted to the said handle and sector-pl ate wit-h a `feather and groove, and the said plate and handle are prevented from moving in the direction of the length ofthe stem by means of a bracket, J, which is secured to the bed-plate or framing of the engine, and which encircles the stem on opposite sides of the said handle and sector-plate.

In the operation of the engine the cutfoif valve G, deriving motion from the eccentric I, works back and forth on the back of the main valve F, and owing to the advanced po` sition of its eccentric it opens the ports d d of the main valve in turn before the said ports commence opening to their respective eylin der-ports l) b as the piston arrives at the end of its stroke. Before the piston has traveled far in the new stroke the movement of the valve G is reversed relatively to F, and it commences to close the port d or d, as the case may be, and cut off the steam. This closing of the port d or d', and consequent cutting off of the steam, is effected at an earlier or later point in the stroke of the piston, according as the cut-oit valve is turnedA toa position in whicli a longer or shorter part of the said valve works over the ports d rl. By turning the valve-stemf to bring the pointed side of the valve nearer to the port-s d d the cutting off is caused to take place later in the stroke, and by turning the stem in the opposite direction an opposite effect is produced, and by turning the said valve far enough in either direction it may be made to cover so little of the main valve as never to close the ports entirely, and so permit the steam to enter the cylinder throughout the whole stroke of the piston, or cover so much as never to entirely uncover the ports d fl', and so to cut olf the steam entirely from the cylinder. In Fig. l

the stem f and in the opposite direction to the piston, and G moving faster than F, 'owing to the eccentric H having only just passed the center. The governoris so connected that by an increased speed of the engine it will be caused to turn the valve-stem f in a direction to bring the longer side, j, of the valve G toward the ports (l cl, and vice versa. Vhen it is desired to have' the steam admitted to the cylinder through a greater or less portion of the stroke, the dog m, before mentioned, is shifted to ahigher or lower notch in the sector-plate, p. Then it is not desiredv to apply the governor in connection with the cut-off, the sector-plate p is tol be xed, and the stem f can be turned by the lever l to bring the valve G to a position to cut off at any fixed point'in the stroke, and secured by dropping the dog on into a suitable notch in the sector-plate. f

Two cut-off valves of substantially similar construction may be used in combination with separate main valves at each end of the cylinder, both of said cut-off valves being attached to the same stem. The two cut-off valves; however, 4will only require to have each one oblique side, as each will only have vto work in connectionl with one main-valve port.

The cut-off valve G may also be constructed flat, operating on a plane surface on the back of the main valve, being in such case so attached to the stem f as to allow of its rectilinear motion at right angles to the motion of said stem 'when the latter is partially rotated on its axis, the oblique ends of the valve and oblique ports producing substantially the same effect as the` cylindrical arrangement above described. The angular-ended eut-off valves, whether cylindrical or fiat, .may also be used in separate-valve-chests, in' connection with oblique ports and oscillating' reciprocating valve-stems, as before described.

That I claim as my invention, and desire to secure by Letters Patent, is

l. The cut-off valve G, having its end or ends oblique to the direction of the movement of the mainvalve and applied to the latter valve, in combination with a stem, f, or its equivalent, by which it is moved transversely to the main valve, and operating substantially as described, in combination with an oblique arrangement of the outer orifices of the mainvalve ports, for the purpose herein set forth.

2. Combining the stem f of the so constructed and applied cut-off valve with a governor by means of a handle or hand-lever, l, a dog, m, a seetor-platap, and an arm, q, substantially as and for the purpose herein described.

ALEXR. K. RIDER. lVitnesses:

RowLAND WALTER,

MARSHALL JONES. 

